If you are retired, you do not have a source of income from a job--you rely on your savings, interest from investments, or the government (e.g., social security in the US). With a job, your salary typically increases every so often to track inflation. When you just have savings, the total value of your money stays the same while the purchasing power of that money decreases. Investment income on your savings (e.g., interest) counterbalances this effect somewhat and government programs typically give out more money to account for the effects of inflation, but neither of these counterbalancing measures may prove sufficient.
The main way in which mercantilism increased the likelihood of conflicts between European powers was that it led to dispute over who could trade where, and disputes over the trade agreements themselves, since every country wanted the "best deal".
